High-speed flute-grinding machine



Sept. 9,` 1958 s. M. BABBITT Y HIGH-SPEED FLUTE-GRINDING MACHINE 8 Sheeiis-Sheet 1 med nay 2v. vm55 @5.5. Munk TQQ QU 7 INVENToR. .sgr//MBABB/TT ATTORNEY Sept. 9, 1958 s. M. BABBITT HIGH-SPEED FLUTE-GRINDING MACHINE 8 Sheets-Sheet 2 Filed May 27. 1955 FIGA INVENTOR. SET//MBABB/TT MKM ATTORNEY Sept. 9, 1958 s. M. BABBITT HIGH-SPEED FLUTE-GRINDING MACHINE 8 Sheets-Sheet 3 Filed May 27. 1955 INVENToR. SET/IMBABB/TT A TTORN V Sept., 9, 1958 s. MBABBlT-r 2,850,849

HIGH-SPEED FLUTE-GRINDING MACHINE Filed May 27. 1955 8 Sheets-Sheet 4 G WS | i I l I l Z0 l 56 C 4/ 45 42F\ M4 5i, .JZ 4/ A V INVENToR. SETIMQBB/TT /50 2/9 BY. 22/ MKM 22o' /2/ 224 ATTORNEY Sept. 9, 1958 s. M. BABBITT lx-IIGH-SPEED FLUTE-GRINDING MACHINE Filed May 27. 1955 8 Sheets-Sheet 6 INVENTOR.

ATTO/@MEV E s, @s mm NTV mm um Sept 9, 1958 s. M. BABBITT 2,850,849

HIGH-SPEED FLUTE-GRINDING MACHINE 8 Sheets-Sheet '7 Filed May 27. 1955 INVENTOR. SETI/MBA BB/ T7' ArToRA/EV HIGH-SPEED FLUTE-GRINDING MACHINE Seth M. Babbitt, Fanwood, N. J., assignor, by mesne assignments, to Eclipse Counterbore Company, Ferndale, Mich., a corporation of Michigan Application May 27, 1955, Serial No. 511,521

12 Claims. (Cl. 51-95) 'This invention relates to means for fluting workpieces and concerns more particularly an improved machine for producing chip utes and cutting edges in tool-steel stock solely for grinding. This application is a continuation-inpart of my earlier tiled application Serial No. 474,461, 'filed December l0, 1954.

The invention is concerned primarily with the development of rotary tools having flutes and cutting edges extending generally axially but helically about the axis and to so produce the utes and cutting edges that the surface of the stock between cutting edges is developed in the form of an unbroken ogee curve that defines the cutting edge, the valley of the flute, and the back of the next preceding cutting edge, such a curved surface having reproduced or reected therein all the rake and clearance allowances necessary for the linished tool. A primary aim of the invention is the production of uted tools having those characteristics in an eicient economical manner.

Another aim of the invention is to produce finished luted workpieces from solid stock entirely by a grinding operation necessitating but a single set-up of the work with relation to the grinding wheel. Prior to this invention uted tools such as end-mills were customarily produced by rough milling the iiutes in two or more set-ups after which the piece was hardened and then tediously straightened, ground to size, and sharpened. The present invention aims to produce similar tools from previously hardened solid stock by a method of grinding that generates in one operation cutting edges finished-sharpened to size and all rake and clearance angles necessary for the finished tool. i

Still another aim of the invention is the construction of a machine embodying readily accessible means for mounting the work and the grindwheel in cooperative re-v lation to produce flutes in the work at an eflicient rate and embodying means for effecting relative movement between tool and work radially and axially of the work, and in the case of helically fluted tools, simultaneously angularly of the Work. The invention further undertakes to provide a machine for grinding utes from the solid in which means are provided automatically operative upon the completion of the grinding of one ilute to index the work relative to the working face of the wheel through a prescribed arc after which the grinding operation of the next flute is automatically instituted. Still a further aim of the invention is to incorporate means selectively operative to impart a progressive rotary motion to the work between indexings simultaneously with or in addition to the combined oscillatory and reciprocatory movement imparted to the work, to the end of producing uted workpieces having relatively wide flutes and substantially cylin-v drical cores.

In attaining the objectives of the invention it is prcr posed to mount a work supporting spindle for rotary, oscillatory, and reciprocatory movement and to provide work-holding means thereon for mounting the blank to be uted. Another portion of the machine provides means for mounting a grindwheel for rotation in a plane genernited States Patent ICC adjusted angularly about a center intersecting the work axis so that the plane of the wheel may lie at an angle to Ithe work axis. Wheel-feed means is also provided to cause the wheel slowly to advance toward the work as the latter rapidly reciprocates. When the machine is set up to grind helical ilutes, the workpiece is oscillated back and forth and simultaneously given a reciprocatory movement to and fro past the wheel. When grinding relatively wide flutes a further movement is incorporated which causes the work to progressively advance (rotationally) during the grinding of the flute. Means are also provided to index the workpiece angularly between llute grinding cycles of operation so that multi-uted tools may be eiciently produced.

Other objects and advantages will be in part indicated in the following description and in part rendered apparent therefrom in connection with the annexed drawings.

To enable others skilled in the art so fully to apprehend the underlying features thereof that they may embody the same in the various ways contemplated by this invention, drawings depicting a preferred typical construction have been annexed as parts of this disclosure and, in such drawings, likecharacters of reference denote .corresponding parts throughout all the views, of which:

Fig. 1 of the drawings is a front elevation of the major portions of a flute-grinding machine embodying this invention. f

Figs. 2 and 3 are end and elevational views of an end mill produced on a machine embodying this invention.

Fig. 4 is an end elevation of the machine with portions broken away more clearly to illustrate parts of the drive.

Fig. 5 is a vertical sectional view of the machine taken substantially along line 5-5 of Fig. 4.

Fig. 6 is a vertical sectional view of the work spindle and work-spindle turret.

Fig. 7 is a horizontal sectional view through the workspindle turret showing portions of the spindle oscillating train, and portions of the turret-rotating and indexing trains.

Fig. 8 is a detail view partly in section of a preferred form of power means for actuating the turret index-lock mechanism.

Fig. A9 is a schematic diagram of a fluid pressure system for actuating the power means illustrated in Fig. 8.

Fig. 10 is a vertical sectional view through the grind- Wheel carriage.

Fig. l1 is a schematic diagram of the several drive trains incorporated in the machine.

Fig. 12 is a schematic diagram of the grindwheel and work-spindle drives.

Fig. 13 is a simplified diagram of the electrical control circuits for the machine.

General structure (Figs. 1, 4, `5, and 6) Referring more particularly to Figs. 1 and 6 of the drawings the machine illustrated includes a main frame in the formof a rectangular base 20 that supports the grindwheel and houses the several drive trains and their coordinating means later to be described. Along the top of the base at the left side, parallel guideways 21 are pro- Work-spindle drive (Figs. 6, 7, and 12) As illustrated more clearly in Fig. 6 the work spindle tea-rented sept. 9, s

WS is mounted on a vertical axis in upper and lower bearings 26 and 27 provided by the turret 25. The upper end of the spindle is provided with a work-driving chuck 28 adapted to grip the workpiece indicated at W which is mounted between centers. The lower end of the spindle WS carries a barrel cam 29 having an endless helical groove 3i) therein that is tracked by a relatively stationary but rotatable follower 31. The barrel cam 29 and its follower 31 are constructed for removal and replacement by others that will produce the ldesired helix angle 4to the ilute to `be formed in the workpiece. Similarly the chuck or collet 28 is replaceable to suit the diameter of the stock to be operated upon.

In order to counterbalance the weight of the spindle WS means are provided in the form of an air cylinder 32.

(see Fig. coaxially aligned with the spindle, and whose piston rod 33 is operatively connected with the spindle by means of a ball-joint type of swivel connector 34. As shown more clearly in Figs. l and 5, an outboard support, indicated generally as S, is provided for steadying the outer end of the workpiece. The support S includes a column structure 35 that rises from the base 20, and is provided with vertical guideways in which a slide 36 is mounted for reciprocation. The slide 36 carries workcentering means 37. The upper end of the slide 36 is connected with a piston rod 38 of another air cylinder 39 that is supported by the column structure 35. Thus it will be seen that when the work spindle is provided with a workpiece, the latter is not only supported at both of its ends but that the air cylinders 32 and 39 yieldingly support the spindle and tend to absorb and overcome the intertia thereof on the high-speed reversals that charaterizes and underlies the success of the instant invention.

High-speed forward and reverse rotations are imparted to the work spindle in accordance with this invention preferably by means of a hand 40 that is wound helically around the spindle WS and its ends drawn taut and secured to a reciprocable slide 41. The slide 41 extends generally transverse the axis of the work spindle and is mounted between upper and lower pairs of guide rollers 42 and 43. The rollers 42 and 43 are mounted for free rotation on supporting arms 44 that project from an singularly-adjustable plate 45. The plate 45 and hence the slide 41 is normally clamped in a position that corresponds with the helix angle of the barrel cam 29 by T- bolts 46 so that when the slide 41 is reciprocated the band 40 rotates the spindle and barrel cam 29 in forward and reverse directions and at the same time assists in the axial movement that is imparted thereto by the barrel cam 29 as the latter is oscillated relative to its stationary follower 31.

Reciprocation of the spindle-oscillating band-slide 41 is effected in this instance by a variable-throw crank mechanism indicated generally at C in Figs. 6, 7, and l2. Such a device may comprise a disc-like member 50 that is secured to the output shaft 51 of a speed-reducing unit 52. The unit 52 is mounted upon a shelf 53 projecting from the turret 25 and is driven by a motor M4 also mounted on the shelf. The face of the disc-like member 50 carries a diametral screw-threaded shaft 55. The shaft 55 is rotatably journaled to the disc 50, as by bearings 56, and is threadably connected with a crankpin 57, the latter being guided and supported in radial guides 58 formed in the face of the disc 50. A connecting rod 59 connects the crankpin 57 with the band slide 41. Thus it will be seen as the crank disc 50 is rotated, the crankpin 57 and connecting rod 59 impart a reciprocatory movement to the band slide 41 and causes a winding and unwinding of the band 40 from the spindle WS. j This winding and unwinding operation causes the spindle to rotate first in one direction and then in the other, and the rotary motions causes axial reciprocation as a consequence of the action of the spindle-carried barrel cam 29 and its relatively stationary follower 31. During the reciprocatory movement, the spindle is effectively counterbalanced by the action of the opposed air cylinders 32 and 39. By the means described it becomes possible to reciprocate and oscillate a Work-holding spindle at exceptionally high rates of speed Without backlash or undue strain on the mechanism. lt will also be seen that the rotary and axial movements of the spindle are positively related in both directions of movement and it is impossible for one character of movement to out run the other as to time or distance which is a very important factor in ute-grinding operations which depend not only upon positively synchronized linear and angular motions but a high frequency of the passes made by the wheel relative to the work.

Gri/zdwheel drive (Figs. 1, 4, 5, 10 and 12) During the reciprocatory and oscillatory movement of the workpiece, the grindwheel G is rotated at grinding speed and caused to feed slowly toward the work axis and upon each up and down movement of the work removes a layer of stock therefrom. A preferred mounting for the grindwheel is illustrated in Figs. l, 4, 5 and l0 in which G indicates a grindwheel that is mounted on an arbor 60. The arbor 60 is journaled in bearings 61 pro.

vided by a swivel-head casting 62 that is mounted to the Wheel carriage 22 and angularly adjustable about a horizontal axis. The wheel arbor 60 mounts a pulley 63 that receives power through a belt 64 from a motor M1. The motor M1 is mounted upon an angularly adjustable bracket 66 that normally is clamped in a xed position to the carriage 22 through the medium of clamp bolts 67. Preferably the motor-shelf bracket 66 is constructed with a second motor platform 66a angularly displaced from platform 66 so that the motor may be mounted on that side when it is desired to swing the wheel arbor over to grind ilutes of the opposite hand.

As indicated in Figs. 4, 5, and 10 the advancing and retracting movements of the grindwheel carriage 22 are under the control of and governed by a rotary cam 70 mounted upon a master-timing shaft 71'. The mastertiming shaft 71 receives rotary motion from a worm and wormwheel drive 72 which in turn receives power through change gears 73 from a speed reducer 74 and a motor M3. The speed reducer 74 and its drive motor M3 are mounted upon an adjustable shelf 76 (Figs. 4 and 5) so that the center distance between the reducer-output shaft and the wormgear shaft may be adjusted to suit the particular speed-change gear combination 73 desired to operate the master-timing shaft and to effect the reciprocatory movements of the grindwheel carriage or slide 22.

The cam 70 is formed with a reduced portion 70a and a gradually ascending portion 70b and is tracked yby a follower 77 mounted upon one arm 78 of a bellcrank lever 79. The lever 79 is pivoted as at 80 to an independently adjustable bracket 81. The other arm 78a of the bell-crank lever engages a roller 82 that is journaled in a bracket 83 carried by the wheel carriage 22. Thus, as the cam 70 rotates the bell-crank lever 79 is rocked and the wheel carriage 22 is caused to advance slowly. At the end of the advancing movement the low portion 70a of the cam 70 reaches the roller 77 and the carriage is returned to its starting position. In the embodiment illustrated the retracting movement of the Wheel carriage is brought about by means of a heavy weight WT that is supended from a lever 84 located preferably exteriorly of the machine. The lever 84 is secured to a rockshaft 85 which carries at its inner end another lever 86. Lever 86 journals a roller 87 positioned to engage the front face of a bracket 88 mounted on the carriage 22. With such an arrangement, the weight WT constantly exerts a substantially uniform force on the carriage 22 tending to move the wheel carriage rearwardly and maintain the `follower 77 against the cam 70.

The grinding of liutes according to the present invention requires that the grindwheel Ibe continually dressed assenzio and trued to maintain the proper form. The dressing operation and the wear incident to theactual grinding operation necessarily reduces the wheel diameter and in the absence of compensation, the operating side thereof would not grind the proper depth of flute. Figs. and illustrate at D a wheel-dressing slide that mount a diamond -dfor movement laterally across the rear face of the wheel to dress the wheel to the required form. As the structure of the wheel-dressing device perse forms no part of the invention claimed herein -it will be suicient to say that the slide D is cam actuated radially and laterally relative to the wheel and causes the diamond to produce thereon the required form. As the slide traverses back and forth in a plane generally perpendicular to the work axis, a cam c causes the diamond to move in and out and the combined movements causes the required form to be developed on the wheel. The dressing operation reduces the wheel diameter and accordingly means are provided to impart to the wheel carriage 22, in addition to the forward feed prescribed by the cam 70, a progressive advancing movement proportional to the rate of reduction in wheel radius and also to impart to the dressing device D an overtaking movement at twice that rate. To those ends the dressing device D is mounted upon a supplemental slide D1 that is supported in guideways provided in the wheel carriage.

The supplemental slide D1 has a nut 185 non-rotatably secured thereto which is engaged with threads 186 on a rotatable screw shaft 187. The shaft 187 is also provided with another set of threads 188 of opposite hand that engage with complementary threads formed in a nut-like extension 83a of the follower carrying bracket 83. The bracket 83 is also in the form of a slide and is mounted in guides 83b provided by the wheel carriage 22. The screw shaft 187 has a wormwheel 89 secured thereto, and the latter is secured to a rotatable shaft 90 which is journaled against endwise movement in the wheel carriage 22. Thrust bearings 91 at each side of the journal bearing allow the screw shaft to rotate freely and at the same time resist axial displacement of the screw shaft relative to the wheel slide. When the oppositely threaded screw shaft is rotated in one direction the roll-carrier slide 83 andthe supplemental slide D1 are urged apart and when rotated in the opposite direction the two slides are brought closer together. However, and inasmuch as the roll-carrier slide abuts the arm '78a of the feeding bell-crank 79, rearward movement of the carrier 83 is prevented and the wheel carriage 22 as a whole moves forward at the rate prescribed by the pitch of the threads 188 and the rate of rotation of the screw 187. The diamond-carrying slide D1, however, moves forward at the rate prescribed by its screw means 185, 186 and this movement is relative to the movement of the wheel slide 22 so that the diamond is caused to advance at a wheel-overtaking speed and effects continual dressing across the rear face thereof. The front edge of the wheel, i. e. that portion of the periphery that engages the work, moves forwardly at the feed rate prescribed by the main feed cam 70.

The feeding movement of the dressing slide relative to the wheel slide is brought about yby a cam-operated ratchet mechanism 92 (Figs. 1, 4, and 11) that is driven by a motor M2 carried on the wheel slide 22. YThe motor MZ drives a speed reducer 94 which in turn drives a cam or eccentric 95 through speed-change gears `96. The cam 95 operates against a roller on one arm of a bell-crank lever 97 whose other arm connects with a ratchet lever 98. The lever 98 carries a pawl 99 that engages ratchet teeth cut on the periphery of a wheel 100. The ratchet wheel 100 is mounted on a worm shait 101 which carries a worm 102 in mesh with the Wo-rmgear 89. Each revolution of the dressing-feed cam 95 thus causes the ratchet wheel 100 to be indexed a Adjustments for flute depth To accommodate workpieces of diiferent diameters, the wheel slide 22 is constructed to be shifted bodily toward or away from the work axis. 'To this end the fulcrum 80 of the wheel-feeding bell-crank 79 is journaled in an adjustable bracket 81 that is supported in guideways 81a (Fig. 4) provided by the main frame. The bracket 81 carries a nut 81h that is threaded on `a manually operated screw shaft 81C. The screw shaft is rot tatably but non-translatably journaled in a relatively stationary lug 81d and carries a wormwheel 81e at its outer end. The wormwheel 81e is engaged by a worm 81jc that is mounted on a manually operable wormshaft 81g. The wormshaft carries a handwheel 81h at its outer end by which coarse adjustments in wheel-slide positions may be obtained, and also a micrometer-dial drop-worm feed device 81j, of conventional construction, by which fine adjustments of the wheel slide may be made. Operation of the wormshaft 81g, through the means described, will effect a repositioning of the Ibellcrank fulcrum 80 so that the extreme IN position of the grindwheel G may be accurately determined. This adjustment may be termed an adjustment for depth of flute and is made preferably when the follower-roll 77 is on the high part of the feed cam 70.

Selective Work-Rotating and Work-Indexing (Figs. 5, 6, 7, 11)

and the latter through bevel gears 118 to worm shaft 119. y

Wormshaft 119 mounts a worm 120 that meshes with a large worrngearA 121 secured to the lower end of the indexible turret 25.

The wormshaft 112 also carries a sprocket 122 which through a chain 123 drives a sprocket 124 on a shaft 125 arranged coaxial with the previously mentioned wormshaft 119. A second magnetic clutch 126 is inserted between shafts 125 and 119 adapted when energized to transmit power at a relatively rapid rate to wormshaft 119 and the turret gear 121. In this way a low-speed transmission and a high-speed -transmission for workturret angular motion is provided, each dominated by a magnetic clutch and both deriving power from a cornmon source. The control means for the clutches 116 and 126 whereby they are not only mutually exclusive in their action but timely operated to effect intermittent progressive rotation of the work turret and/or in as at 132a to the main frame 20 and its free end is connected with a pair of fluid-operated cylinders 134e and 134b arranged to swing the lever in the plane of the lugs 131 periodically from lug-locked to unlocked position and to an intermediate stop position. As illustrated more clearly in Fig. 7 the lock lever 132 carries a U- shaped cam-piece 135 having a long leg 136 and a short leg 137. The cam-piece 135 is preferably mounted to the lock lever in rubber or other slightly yieldable material 138. The opening 135a between the legs of the cam-piece is generally wedge-shaped and adapted to engage any one of the disc lugs 131 and thereby accurately center the turret and work spindle. When the lock lever is in the extreme outward ,position -a- Fig. 7, the disc lug 131 is released and the disc 130 free to turn in the direction of the arrow. When the lock lever is in position -b the long leg of the cam-piece 135 is positioned in the path of movement of the lugs 131 and the next succeeding lug is caused to abut against it. When the lock lever is in position -c-- the stopped lug is wedged in the pocket 135a of, the cam-piece and the turret accurately centered and locked in position. Preferably the pivot side of the pocket 135a in the lock piece is formed with a true radius generated from the pivot 132a to maintain accuracy in the indexed positions.

The structure of the lock-lever-operating cylinders 134a and 134b is illustrated more clearly in Fig. 8 in which the upper cylinder 134:1 is of conventional structure and whose rod pivotally connects with the free.end of the index-lock lever 132. The lower cylinder 134b has its rod 139 also pivotally connected with the lever 132 but the cylinder contains an annular stop ring 140 fixed to the inner wall of the cylinder intermediate its ends. The piston rod 139 is provided with an enlarged abutment 139a at its inner end adapted to pass through the stop ring 14) and to be engaged at either side thereof by oating-piston heads 141 and 142. Each of the cylinders is provided with a fluid inlet and a fluid exhaust port at opposite ends through whichvuid under pressure is admitted to actuate the power cylinders. Solenoidoperated valves and a source of fluid pressure, later to be referred to, are provided for this purpose. In the position of the parts shown in Fig. 8, pressure fluid acting behind iloating piston-head 142 has moved the latter t0- ward the left to a position about to abut the stop ring 140. Movement of the piston head 142 acting against the enlarged end of the rod 139 carries the rod and lever 132 to the left. When the oating piston 142 reaches the stop ring 140, movement stops and the lock lever 132 comes to rest in the intermediate position -b- (Fig. 7).

If pressure fluid is then admitted to the right end of the upper cylinder 134:1 its piston is moved further tO the left and the lock lever is moved to the disengaged position -a- (Fig. 7) permitting the turret to index. During such further movement the rod 139 moves away from the piston head 142. To move the lock lever 132 back to its intermediate position, the right end of the cylinder 134:1 is vented and fluid pressure in the left end of the lower cylinder 134b moves the floating piston 141 which abuts the headed end of the rod 139 toward the right until the piston 141 engages the top ring 140. This movement swings lever 132 again to its intermediate position -bwhereat the long leg 136 of the lock cam lies in the path of movement of one of the lugs 131 carried on the index plate 130. To center and locl; the turret in the indexed position, fluid is admitted to the left end of the upper cylinder 134g and moves the piston thereof further to the right which carries the lock lever 132 to position -c--. During this movement the rod 139 of the lower cylinder slides through the floating-piston head 141.

In the system illustrated diagrammatically in Fig. 9 uid pressure which may be air under pressure, enters 8 the system through a line 252 and after passing a pressure-reducing valve 253 branches into two lines 254 and 255. Pressure line 254 is connected with the inlet port of each of the solenoid-operated valves 250 and 251, whereas pressure line 255 leads to a second pressurereducing valve 256.

The work port of solenoid valve 250 connects via line 257 with the small end of the power cylinder 134:1, and the .work port of valve 251 connects via line 258 with the large end of the cylinder 134a. The output side of the second reducing valve 256 connects with both ends of the centralizing cylinder 134b by line 260. Thus, when both solenoid valves are in cylinder-venting position (see position of valve 251) the continuous pressure applied to both ends of the centralizing cylinder 134b actuates both of its oating pistons 141 and 142 toward theA central-stop position, whereupon the piston rod 139 and lock-lever 132 are moved accordingly. However, if one of the solenoid valves are in an effective position (see position of valve 250) the lhigher pressure moves the piston of power cylinder 134:1 in opposition to the pressure in centralizing cylinder 4134b and the lock-lever 132 is moved out ofthe mid-position -b-- into lock position -cor to released position -aas the case may be.

Operation (wheel feed) Fig. J3

The operation of the machine may be best understood by referring yto the schematic electrical diagram Fig. 13. In this diagram the .legends M1, M2, etc. represent the -coils of magnetic starting switches of the lseveral motors, which motors are for lconvenience correspondingly identied in the other gures. The contactors of the motor starters are `conventional design and have not been illustrated. The control circuit as a whole is a low voltage secondary deriving power from a transformer 200. The push buttons Wheel-Stop and Wheel-Start control 4the operation of the wheel motor M1. When the Wheel- Start button is pressed a circuit is completed from lines 201 through the normally closed Wheel-Stop button to line '202 and starter coil M1 which starts the ywheel motor running and completes Aa holding circuit indicated by switch m1 around the Start button. Current in line 202 also energizes starting coil M6 of the work-spindle indexing motor M6 and the Werk-index motor starts. The operator then pressed the Cycle-Start button which completes a `circuit from line 202 through the Cycle-Stop button to line 204 to the starter coil M3 of the cycle motor M3 which drives the main camshaft 71 and cam 70. When the starter M3 has been energized a holding circuit is completed through switch m3- to the live side of the Cycle `Start Switch. The work reciprocating motor M4 as well as the coolant pump motor M5 are con nected in parallel with the cycle motor M3 and all three motors start together. logswitches 205 and 206 are incorporated in the circuits to motors M3 and M4 to effect momentary operation useful in setting up the machine. A selector switch 208 is incorporated in the circuit of the wheel-truing motor so that the latter may be operated continuously, as to give the initial form to a new wheel, or intermittently, after the initial truing operation, when the machine is performing automatically. When the switch 208 is turned to Continuous a signal light 209 indicates that fact.

As illustrated in Figs. 4 and ll the master cam-shaft 71 carries a series of discs at its forward end, each of which is constructed to carry one or more adjustable switch-operating dogs. The Outer disc 4 carries one or more dogs positioned to actuate switch 210 in the circuit of the wheel truing motor. As many dogs are mounted on the disc as may be needed to actuate the wheel truing motor that many times in the course of grinding a single llute. The disc and dog marked 5 in Fig. ll is on the shaft carrying the wheel-truing cam and operates on each revolution of this shaft, indicative of one pass of the diamond across the wheel face, to stop the operation of the wheel truing motor by openingswitch 211 until another dog on the timing disc 4 starts the motor M2 by again closing tie starting switch 210. On

completion of the grinding of all of the utes, switch dog 6 which is back-geared to the main cam-'shaft 71 opens switch 212 in the holding circuits of motors M3, M4 and M5, and the latter stop.

The back-gears for the stopping-switch dog 6 and switch 212 are indicated at 213 in Fig. 1l. These are removable change-gears having a ratio appropriate for the number of ilutes to be ground, i. e. 2, 3, 4, etc. and receive power from the rnain camshaft 71 which makes one revolution per flute.

The limit switch LS1 in the circuit lto thet-ruing motor M2 is normally closed but is opened by a dog 215 on the feed-nut -bracket S3 when the truing yslide has been advanced the recommended maximum distance in its operation of reducing Wheel diameter.

Operation (control of work-rotation and indexing) The -controls for the high-speed and low-speed magnetic clutches 116 and 126 in the turret-index train and the contro-ls for the solenoid-operated valves that operate the lock-lever power cylinders 13401` and 135b are illustrated diagrammatically in the lower part of Fig. 113. The members marked 1, 2, and 3 are discs mounted upon-the main cam-shaft 71 and each carries one or more adjustable dogs adapted to actuate start switches 216, 217, and 218 respectively. Dogs 219, 221, and 223, are mounted to the underside of the turret-indexing plate 130, and there is one set of such dogs for each iiute to be ground in the work. For two-flute ywork there will be two sets ofthe dogs, for three-ilutework there will be three sets of the dogs, etc., the sets being equally spaced about the discs. When, however, two-flute work is to be ground, the feed-clutch `coil 116K is initially energized to cause the spindle turret 2S to travel `at a feed rate for the required angular distan-ce determined lby the setting of additional stop lugs 131 and turret disc cams, after which the index-clutch `coil 126K is energized to effect high-speed movement of the turret frame 25 to thenext tinte-grinding position. The stop lugs 131 and switch cams 219, 221, and 223 will conform innumber and spacing to suit the feed and index movements and/ or the flute number. Stop switches 220, 222, and 224 respond to the movement of the dogs to eiect locking and unlocking of the disc and the high and low speed movements thereof.

In the position shown in Fig. 13, switch 217 is closed on one side and a circuit is established between line 201, and 225 through disc switch 222 to line 226 and solenoid A. Energization of valve solenoid A effects shifting of the valve 250 to a position such that air under regulated pressure is directed to the small end of the power cylinder 134a whereby the index-lock lever 132 is moved In in `locked relation with one of the lugs on the turret disc 130. As the main cam-shaft turns the dog on switch disc 2 operates switch 217 Iand opens the circuit to the locking solenoid valve 250 and the valve shifts by spring pressure and vents the small end f the power cylinder 134a. When the clamping pressure is released from cylinder 134a, the pressure applied continuously to both ends of the centralizing cylinder 134k centralizes the piston rod 139 and the lock-lever 132 is moved to its intermediate position.

As the switch 217 opens the circuit to line 22S it closes on the other side and completes a circuit via line 227, switch 216, switch LS2 to the relay 126R provided for the magnetic clutch 126 in the turret-index high-speed train. Simultaneously, disc dog 3 operates switch 218 and closes circuit 228, switch 224, line 229 to Valve s-olenoid yB. Energization of solenoid B shifts valve 251 to a position such that pressure air is admitted to the ilarge end of the power cylinder 134:1 and the piston and the lock lever 132 move out of the stop position to unlocked position, and with the index'motor running and the clutch 126 engaged, the work-spindle turret-indexes? one position. However, indexing can only occur if the vwheel slide is retracted, and to ensure that the wheel is out of the work, limit switch LS2 is inserted in the circuit of the index-clutch coil 126K and which is moved to closed .position by a dog on the slide 22 as the latter reaches its retracted position. 4Accordingly should the weigh WT that retracts the slide be a Ilittle sluggish in 4 its action and the slide fails to return, the indexing of the turret is delayed.

Shortly after indexing starts, the turret-disc cam 223 rides oft the switch 224 of valve solenoid 'B and de-energizes the latter. The valve 251 'shifts by spring pressure to venting position, and the pressure that is continuously Vapplied to the ends of the centralizing cylinder 1341) returns the piston rod and the attached lock lever 132 to its intermedi-ate or stop position -ab- (Fig. 7) which places the long leg 136 of the lock piece int-o the path of movement of the next succeeding disc lug 131.

As the previously clamped turret lug 131 moves out of position the turret dog 221 rides ott switch 222 and the latter opens thereby opening a portion of the circuit to disc-clamping solenoid A and holding the latter deenergized until the next turret lug 131 arrives in position. At the same time turret dog 219 rides oit switch 220 and the latter opens to break the circuit to the coil of a timedelay jumper switch 230 and the latter closes. The closing of switch 230 keeps current supplied to the indexclutch coil 126K until the next turret dog 219 arrives in position. When that occurs the switch 220 closes and energizes the `coil of the timer and after a predetermined time, the switch 230 opens breaking the circuit to the index clutch coil 126R. The time-delay switch is of the pneumatic. type and the delayed timing of the opening of switch 230 is only that interval required to ensure rm clamping of the turret by the action of the locklever 132 with the power-index clutch 126 engaged and tending to drive the turret. A limited slippage of the clutch 126 is intended during the clamping operation. The work-spindle turret is thus indexed and reclamped in proper angular position for the performance of the grinding operation of the next ute.

The main cam shaft 71 continues to revolve and feeds the wheel slide 22 toward the reciprocating and oscillat-` ing workpiece until the flute is ground to the proper form and deptirwhereupon the wheel slide is caused to be retracted and the indexing cycle is repeated. After the required number of flutes have been ground, the backgeared switch dog 6 engages and operates switch 212l which opens the holding circuits to starters M3 and M4 the manual Stop button.

positioned as to engage the switch arm of the switch 216- and move it at the proper time to its other side thereby completing a circuit to the coil 116R of the magnetic clutch 116 in the slow-speed or feed transmission (11S- 118, Fig. ll) to the turret wormgear 121. The switch 216 is of the selector-switch type so that at any one instant only one lof the magnetic clutches in the drive to the turret can be effective. During the slow-speed rotary Imovement imparted to the turret the grinding operation progressively widens the ilute until the proper depth has been reached after which the wheel slide recedes. During the receding movement the cam-shaft disc-dog 1a rides olf the switch arm of selector switch 216 and the latter closes on the fast-speed or index-speed side in preparation for the next indexing operation.

Without further analysis, the foregoing will so fully reveal the gist of this invention that others can, by applying current knowledge, readily adapt it for various utilizations by retaining one or more of the features that, from.

1 1 the standpoint of the prior art, fairly constitute essential characteristics of either the generic'or specific aspects of this invention and, therefore, such adaptations should be, and are intended to be, comprehended within the meaning and range of equivalency of the following claims.

Having thus revealed this invention, I claim as new and desire to secure the following combinations and elements, or equivalents thereof, by Letters Patent of the United States:

l. In a machine adapted to grind helical flutes in previously hardened tool stock the combination of a rotatable and axially shiftable work spindle adapted to mount the stock to be ffuted, a rotatable grindwheel mounted for movement generally radially of the stock and in a plane transverse the axis thereof, power means for moving the grindwheel toward and away from the axis of the stock, power means for imparting oscillatory movement to the work spindle about the longitudinal axis thereof and reciprocatory movement to the work spindle in a direction substantially parallel to the longitudinal axis thereof and to stock mounted on the spindle whereby to cause the grindwheel to grind a helical channel along the stock, means limiting the movement of the grindwheel radially toward the axis of the stock a predetermined distance whereby to limit the depth of the channel to be ground, means operating in timed relation with the movement of the grindwheel away from the axis of the stock to effect an indexing of the stock through a predetermined arc during the oscillatory and reciprocatory movements there of, means operative automatically to effect a repetition of the channel grinding operation in the stock in the newly indexed position, and means discontinuing grindwheel and stock movements on completion of the grinding of a selected number of channels in the stock.

2. In a machine of the character described the combination of a rotatable and axially shiftable work spindle adapted to mount the stock to be fluted and to impart thereto similar movement, a rotatable grindwheel operable on the stock in a plane transverse the axis thereof, a shiftable support for said grindwheel, means including a cam for shifting said support cyclically at a feed rate toward the axis of the stock and at a relatively rapid rate away from the axis of the stock, power means for imparting oscillatory movement to the work spindle about the longitudinal axis thereof and reciprocatory movement to the work spindle in a direction substantially parallel to the longitudinal axis thereof and to stock mounted on the work spindle whereby to cause the grindwheel to grind a helical channel on the stock, means operating in timed relation with the movement of the grindwheel away from the axis of the stock to effect movement of the work spindle and stock angularly through a predetermined arc during the oscillatory and reciprocatory movements thereof for the commencement of another grinding operation on the stock in the newly indexed position.

3. In a machine of the character described adapted to grind helical flutes in previously hardened tool stock the combination of a rotatable and axially shiftable work spindle adapted to mount the stock to be fluted, a rotatable grindwheel mounted for movement generally radially of the stock and in a plane transverse the axis thereof adapted to operate upon the stock, power means fotimparting rapid oscillatory movement to the work spindle about the longitudinal axis thereof and reciprocatory movements to the work spindle in a direction substantially Aparallel to the longitudinal axis thereof and to stock mounted on the work spindle whereby to cause the grindwheel to grind a helical channel on the stock, and pneumatic means operable on the work spindle and stock in an axial direction for absorbing the kinetic energy of the work spindle and stock on reversal of motion.

4. In a flute grinding machine of the character described the combination of a work-supporting spindle, a frame journaling the spindle for oscillatory movement about the longitudinal axis thereof and reciprocatory movement in a direction substantially parallel to the longitudinal axis thereof, means journaling said frame for angular movement about an axis coincident with the axis of the spindle, means carried by the frame for oscillating and reciprocating said spindle, additional means connected with the said frame for moving the frame angularly intermittently selectively at a feeding rate and at a relatively rapid rate, a grindwheel positioned in operative relation to a workpiece supported by said spindle and means for rotating the grindwheel to effect a grinding operation during the oscillatory and reciprocatory movements of the spindle whereby to form a helical flute in the workpiece, means rendering said frame moving means operative at a feeding rate during said grinding operation whereby the helical flute formed in the workpiece is progressively widened, and means rendering said frame moving means operative at its said relatively rapid rate 4on the conclusion of the flute-widening operation to index the workpiece angularly to a new position.

5. In a grinding machine of the character described the combination of, an indexible carrier, a work-supporting spindle journaled in the carrier `for rotary and axial movement said spindle having work-holding means adapted to support a workpiece, means connected with said spindle about the longitudinal axis thereof for oscillating the spindle and additional means connected with the spindle and responsive to the oscillatory movement thereof for reciprocating said spindle in a direction substantially parallel to thelongitudinal axis thereof, pneumatic means connected with the spindle for counterbalancing the weight thereof, a rotary grindwheel adapted to be positioned with its rim in operative relation with a workpiece supported by said spindle, means for feeding said rotary grindwheel into engagement with a workpiece held by the spindle whereby to grind a groove therein at a helical angle which is a function of the oscillatory and reciprocatory motions partaken by the work spindle, power means for indexing said carrier, and means operable at the conclusion of a grinding operation of one groove to render said power indexing means effective to index the carrier a predetermined angular distance whereby to present a new area of the `workpiece to the action of said grindwheel.

6. In a grinding machine of the character described the combination of, a rotary carrier, a work-supporting spindle journaled in the carrier for rotary and axial movement relative thereto, means connected with said spindle for oscillating the spindle about the longitudinal axis thereof and additional means connected with the spindle for reciprocating said spindle in a direction substantially parallel to the longitudinal axis thereof, carrier indexing means, a rotary grindwheel adapted to operate upon a workpiece supported by said spindle, means including a master camshaft for feeding said grindwheel into engagement with a workpiece mounted to the spindle, and control means including said master camshaft for rendering said carrier indexing means cyclically effective.

7. In a flute grinding machine of the character described the combination of a work-supporting spindle, a frame journaling the spindle for oscillatory and reciprocatory movement, means journaling said frame for angular movement about an axis coincident with the axis of the spindle, means carried by the frame for oscillating said spindle about the longitudinal axis thereof and reciprocating said spindle in a direction substantially parallel to the longitudinal axis thereof, additional means connected with the said frame for moving the frame angularly intermittently, a grindwheel positioned in operative relation to a workpiece supported by said spindle and means for rotating the grindwheel to effect a grinding operation during the oscillatory and reciprocatory movements of the spindle whereby to form a helical flute in the workpiece, means rendering said frame moving means operative at the conclusion of a flute grinding operation to index the work spindle angularly to a new position, and control means ,operative on the conclusion of a selected number of work-spindle-indexing movements and flute grinding operations to discontinue the operation of said machine.

8. In a grinding machine of the character describedpthe combination of, a work-supporting spindle journaled for rotary and axial movement in and relative to an indexible carrier, means connected with said spindle for oscillating said spindle about the longitudinal axis thereof and reciprocating the spindle in a direction substantially parallel to the longitudinal aXis thereof, a grindwheel adapted to operate upon a workpiece supported by said spindle during dwell periods of the carrier, means connected with the carrier for indexing the carrier intermittently, and intermittently operable carrier-clamping means engageable with the carrier for clamping the carrier in indexed position during a grinding operation.

9. The combination of claim 8 in which said carrier is provided with a plurality of spaced lugs and said clamping means comprises a notched lever movable into and out of engagement with said lugs.

l0. In a ute grinding machine having a rotaryA and indexible carrier adapted to support a workpiece to be ground and a grindwheel movable cyclically into and out of engagement with the workpiece the combination of means for moving the grindwheel, power transmitting means connected with the carrier comprising a low-speed transmission and a high-speed transmission for moving the carrier, clutch means in each of said transmissions, and means responsive to a movement of the grindwheel out of engagement with the workpiece to render one of said clutch means eective to move the carrier.

11. The combination of claim 10 including carrierclamping means, and means responsive to the means for moving the grindwheel to render the carrier-clamping means ineiective prior to rendering said clutch means effective to move the carrier.

12. In a ute grinding machine of the character described the combination of a work-supporting spindle, a frame journaling the spindle for oscillatory movement about the longitudinal axis thereof and reciprocatory movement in a direction substantially parallel to the longitudinal axis thereof, means journaling said frame for angular movement about an axis coincident with the axis of the spindle, means carried by the frame for oscillating and reciprocating said spindle, additional means connected with the said frame for moving t'he frame angularly intermittently selectively at afeeding rate and at a relatively rapid rate, a grindwheel positioned in operative relation to a workpiece supported by said spindle and means for rotating the grindwheel to eiect a grinding operation during the oscillatory and reciprocatory movements of the spindle whereby to form a helical flute in the workpiece, means rendering said frame moving means operative at a feeding rate during said grinding operation whereby the helical tinte formed in the workpiece is progressively widened, means rendering said frame moving means operative at its said relatively rapid rate on the conclusion of the tinte-widening operation to index the workpiece angularly to a new position, and means including a wheel-trilling device operative on the grindwheel throughout the flute grinding operation to maintain the grindwheel in proper form. i

References Cited in the le of this patent UNITED STATES PATENTS 1,594,407 Durkee Aug. 3, 1926 1,622,628 Durkee Mar. 29, 1927 1,899,654 Ward Feb. 28, 1933 1,976,818 Ward Oct. 16, 1934 2,099,674 Bullock et a1. Nov. 23, 1937 2,547,981 Scone Apr. 10, 1951 UNTTED STATES PATENT oEETCE u CE TWENTE @F E@ @NGN Patent No@ 2,85%849 September 9:, 1958 Seth. Babbi It is hereby certified that error appears in the -prnted specification o' the above Ivmrnbez'ed patent Tequring correction and that the Said Let-ters Patent should read as Corrected below.,

Column IL9 line 189 for "for" Tead by eolumn 2p line 20. for "Tha-eef" read m hereof en; oolumn 33 line 323 for "ntertia" read inertia am; lines 32 and 33g fola "olaaraterzes" read m characterizes m; column 5y line 6r9 for' "m0111125" read w mounts me; column 8, line 3.4,, for "as a Whole" read m as Whole m; line 45p for "pressed" read m presses mg; eolumn 9;, line 24g for "13513" read we 13MB we Signed and sealed this 25th dey of November 1958.,

(SEAL) Attest:

MRM@ AXLINE EoEEET o. WATSON Attestng Officer Commissioner of Patents 

